Taking into consideration the quality of air, it is necessary to ensure a continued reduction of the gaseous emissions that are produced by the maritime transport. The most effective solution of this serious worldwide problem is application of a suitable fuel mixture, which contains a bio-component, i.e. the biofuel. The presented scientific study is focused on influence of the biofuels on production of the gaseous emissions in the case of a diesel auxiliary engine, which is used in the ship transport. There were created various fuel mixtures with different content of the bio-component in order to investigate their emission characteristics. The individual experimental measurements were performed at the different engine loading levels and using a variable engine speed spectrum. The obtained results demonstrated a significant influence of the fuel mixtures on the whole combustion process, on the heat release process, on the pressure time behaviour as well as on the engine emission characteristics.

This scientific study is focused on the analysis of an influence of the experimental diesel fuel mixtures containing various portions of the biocomponent on the unregulated gaseous emissions generated by a diesel motor vehicle, which is equipped with the diesel engine utilizing the direct fuel injection system “common rail”. The main reason for the choice of this engine type was its wide usage in the current vehicles. The experimental diesel fuel mixtures were created as a mixture of the standard low-sulfur diesel fuel with the biodiesel, using various mixing ratios. The experiments were realized by means of a special 13-regime engine test cycle, which was intentionally developed for the diesel combustion engines. All the individual experiments were performed on the base of the given test cycle with 13 different operational modes. The obtained results offer a complex view on the generation of the unregulated emissions with regard to the operational conditions and taking into consideration operational loading of the given experimental engine.

The subject of the research presented in this article is the dimensional optimisation of the box structure of the main girder for overhead cranes, with the aim to reduce the main girder’s own weight. Described are the applied optimisation methods and also the problems arising during the optimisation process. Loss of shape stability is analysed in more detail, as well as the methods determined for a constructional proposal of the girder cross-section. The developed optimisation procedure is a combination of the calculations, performed in the MS Excel environment, with the simulation of a parametrically modelled girder realised using Dassault Systèmes SolidWorks software v. 2023. Using the example of optimisation of an overhead crane girder with a lifting capacity of 50 tons, the effectiveness of the proposed optimisation procedure is declared, where the existing overhead crane box girder is compared with the optimised cross-section of the box girder.